1. Field of the Invention
The present invention relates to a compressor provided with a first and a second member relatively slidably contacted with each other, and particularly to the improvement in the sliding durability of a coating layer formed on the sliding surface of the two members for the purpose of ensuring contact slidability.
2. Description of the Related Art
In general, a swash type of compressor is provided with a cylinder block forming part of the housing, a plurality of pistons reciprocatively housed in a plurality of cylinder bores which are formed in the cylinder blocks and a swash plate which is fixed on a drive shaft in an inclined state in a crankcase or which is inclination movably provided to the drive shaft. Each of the pistons is movably connected to the peripheral portion of the swash plate through a pair of shoes. The movable connecting construction allows the rotary motion of the drive shaft and the swash plate to be converted into a reciprocating motion of the piston.
For such a swash type of compressor, it has become important to avoid seizure between the swash plate and the pair of shoes which are directly contacted with both surfaces of the peripheral portion of the swash plate, and to reduce friction between the swash plate and the shoes for the reasons explained below. For a swash type of compressor, atomized lubricating oil is carried by a coolant gas and is supplied to each of the portions of the compressor for the purpose of effecting lubrication. However, lubricating oil remaining in and adhering to the sliding surface of the swash plate is washed by the coolant gas before the atomized lubricating oil reaches the swash plate, and the swash plate surface is likely to become dry where the swash plate surface is deficient in lubricating oil. As a result, the swash plate and the shoes are forced to start sliding under dry conditions. The sliding conditions, namely, the sliding environment, of the swash plate is thus very severe. Moreover, so-called new refrigerant, such as R134a, which have recently started to be used in place of conventional cooling refrigerant for the purpose of protecting the ozone layer are more likely to manifest the dry state than the conventional refrigerant. Improvement in the lubricity of the swash plate surface has therefore been required still more.
Conventional technologies which are intended to solve such problems by surface treating the swash plate are disclosed in Japanese Unexamined Patent Publication (Kokai) No. 60-22080 (Japanese Examined Patent Publication (Kokoku) No. 5-10513), International Publication WO 95/25224 and Japanese Unexamined Patent Publication (Kokai) No. 8-199327.
Of these conventional technologies, the technology disclosed in Japanese Unexamined Patent Publication (Kokai) No. 60-22080, for example, comprises forming, on the metallic base material of a swash plate, a solid lubricating layer prepared by binding molybdenum disulfide and graphite with an adhesive such as a phenolic resin. The solid lubricating layer improves the lubricity of the sliding portion surface of the swash plate, makes the contact slidability of the swash plate and the shoes excellent, and improves the seizure resistance of both members.